Memory cards are known in the art and contain intelligence in the form of a memory circuit or other electronic program. Some form of card reader reads the information or memory stored on the card. Such cards are used in many applications in today's electronic society, including video cameras, digital still cameras, smart phones, PDA's, music players, ATMs, cable television decoders, toys, games, PC adapters, multi-media cards and other electronic applications. Typically, a memory card includes a contact or terminal array for connection through a card connector to a card reader system and then to external equipment. The connector readily accommodates insertion and removal of the card to provide quick access to the information and program on the card. The card connector includes terminals for yieldingly engaging the contact array of the memory card.
The memory card connector often is mounted on a printed circuit board. The memory card, itself, writes or reads via the connector and can transmit between electrical appliances, such as a word processor, personal computer, personal data assistant or the like. With circuit board mounted connectors, the terminals of a connector include tail portions which are connected to appropriate circuit traces on the printed circuit board by various systems, such as surface mount technology where the tail portions are reflow soldered to the circuit traces. Through hole technology involves inserting the tail portions of the terminals into the holes in the printed circuit board for connection, as by soldering, to circuit traces on the board and/or in the holes.
Such memory card connectors, including those mounted on printed circuit boards, often include a grounding shield which substantially covers at least the contact areas of the terminals, while also effecting grounding of the connector. Mounting the shields often is difficult, particularly when the connector is mounted on a circuit board.
FIG. 1 shows a shielded, board mounted memory card connector, generally designated 12, according to the prior art. The connector includes a housing or body 14 which mounts a plurality of signal terminals 16 which have contact portions extending forwardly of the body. The terminals have tail portions which are connected, as by soldering, to appropriate circuit traces on a printed circuit board 18. One or more grounding shields 20 cover the terminals. The grounding shields have tail portions 20a which are connected, as by soldering, to appropriate ground traces on the circuit board either by surface mount technology or through hole technology. Problems occur with the ever-increasing miniaturization of such connectors as well as the ever-increasing density of the connector terminals. Short circuits can occur between adjacent tail portions of the terminals and/or the grounding shields, resulting in poor connections. Special tools are required to detach the connector from the board if short circuits or poor connections are found. This not only must be performed with very skillful techniques, but considerable time and material is wasted.
FIG. 2 shows a prior art system designed to avoid the problems described above in relation to the prior art connector of FIG. 1. Similar systems can be derived from U.S. Pat. No. 5,711,679 as well as Taiwan Patent Nos. 5216014 and 86206167. Other than the fact that the connector shown in FIG. 2 is a “dual port” connector involving a pair of stacked connectors, generally designated 12A, the connectors again are designed for mounting on a printed circuit board 18. In this prior art system, a pair of header connectors 22 are mounted on the circuit board. Each connector 12A includes a plurality of terminal pins 24 projecting rearwardly therefrom. Each connector includes a grounding shield 26 having tail portions 26a projecting rearwardly from the connectors generally parallel to terminal pins 24. In order to avoid the problems associated with the solder connections described above in relation to FIG. 1, the prior art system of FIG. 2 employs a pair of daughter printed circuit boards 28 to which terminal pins 24 and tail portions 26a of grounding shields 26 are terminated, as by soldering. The daughter boards are inserted into header connectors 22 mounted to the top of circuit board 18. Although the system of FIG. 2 eliminates some of the problems of the prior art of FIG. 1, since the terminals of header connectors 22 are soldered to circuit board 18, and terminal pins 24 and tail portions 26a are soldered to daughter boards 28, the number of soldering points is significantly increased. This increases the resistance of the connector, reducing the conductive efficiency thereof. The significantly increased number of solder points logically increases the chances of poor solder connections.
Another system of the prior art is shown in Taiwan Patent Application No. 87206371 and as depicted in FIG. 3 to eliminate the problems of the prior art shown in FIG. 1. Specifically, FIG. 3 shows that connector 12 includes a single grounding shield 20A which spans the entire length of the array of terminals 16. The shield has a pair of grounding feet 20a which are disposed outside the array of signal terminals. The grounding feet are soldered to grounding pads on circuit board 18 outside the terminals and, thereby, does not interfere with the solder connections of the terminals. Unfortunately, the relatively large, single grounding shield is fixed to the circuit board at only two locations and has a tendency to become broken-away from the board.
The present invention is directed to solving the myriad of problems described above in relation to the prior art systems shown in FIGS. 1–3 and described above.